Dog may be man’s best friend, but the bond between graduate student Lindsay Jones and her yellow lab is even stronger.

After struggling with two heart conditions that caused her to lose consciousness, Jones looked to her two-and-a-half-year-old lab Amber for a solution. Amber can detect changes in Jones’ heart rate that are caused by either neurocardiogenic syncope — in which it drops below a healthy level — or postural orthostatic tachycardia syndrome — in which it spikes.

“I was passing out a lot,” Jones said. “And I didn’t want to have a roommate forever.”

When she detects a problem, Amber either stares at her owner or walks to the end of her leash. This is Jones’ signal to lie down and let Amber sit atop her until her heart rate returns to normal.

Doctors are still unable to identify what specific warning signals Amber picks up from her owner.

“While science has not exactly determined how the dogs do this, the tight bond formed by the dog and the human is one where each is very sensitive to changes in one another,” physician and program director for the Aria Jefferson family medical residency Rob Danoff told the Philadelphia Inquirer.

The effectiveness of their relationship, however, is clear.

“I haven’t passed out in five months since I’ve had her,” said Jones. “That’s the first time that’s happened in the last five years.”

Jones proved the extent of her abilities with Amber by her side by running a half marathon this past October. Nonetheless, she is still adjusting to her new lifestyle.

“I get noticed all the time, which is not a thing that I’m used to,” Jones said. “I’m just going to the grocery store and people feel the need to know my whole life story, and I’m just trying to get milk.”

Canine Partners for Life, the organization that matched Jones with Amber, works to ease the transition for its clients by offering training and support classes.

According to its website, CPL “is committed to providing support and follow-up to our teams as they grow and change.”

CPL paired Jones with Amber with the Jones' lifestyle in mind.

“She’s feisty. I’ve never met a dog with more attitude,” Jones said. “I never have to question what she’s thinking because she tells me... that’s why I love her.”

Amber uses her energy to perform a variety of other useful tasks. These include paying cashiers and retrieving Jones’ phone from a different room. The dog enjoys constantly working.

“Sometimes I’m like ‘just lay down’ and I’m this close to losing it,” Jones said. “But then I remember that she saves my life, so it’s okay.”